Oil well pump with permanent connections and a plunger therefor

ABSTRACT

A sucker rod pump for use in oil wells is disclosed which has its component parts permanently joined together by means of swaged joints. There is also disclosed a plunger for use in a sucker rod pump which includes a mandrel with plunger sections resiliently mounted thereon whereby eccentricities between the mandrel, the sections, and the barrel may be compensated for by relative radial motion between the sections and the mandrel.

United States Patent 51 Sept. 5, 1972 Meripol [54] OIL WELL PUMP WITH PERMANENT CONNECTIONS AND A PLUNGER THEREFOR [72] Inventor: Robert B. Meripol, Dallas, Tex.

[73] Assignee: Dreser Industries, Inc., Dallas,

Tex.

[22] Filed: Nov. 2, 1970 [21] Appl. No.: 86,211

[52] US. Cl. .417/547, 417/554, 285/382.2 [51] Int. Cl ..F04b 21/04, F04b 39/10, F161 13/14, F161 19/04 [58] Field of Search ..417/448, 449, 450, 547, 554, 417/545, 548; 285/222, 382, 382.1, 382.2, 382.4, 382.5

[56] References Cited UNITED STATES PATENTS 2,134,311 10/1938 Minor et al. ..285/222 X 2 a: w i! ii 7B :1 is 80 M ii:

B2 sli t: 36 i i ii ii: in: 68 ii: t xi 66 iii 58 as F -60 58 iii IE IS iii 58/? ti: ii: iii so 64 58 e2 s so 3,146,725 9/ 1 964 Harris ..417/554 3,431,744 3/1969 Veilex et al ..417/554 X 3,596,939 8/1971 Gibson ..285/382.2 X

Primary Examiner-Robert M. Walker Attorney-Robert W. Mayer, Thomas P. Hubbard, Jr., Daniel Rubin, Raymond T. Majesko, Roy L. Van Winkle, William E. Johnson, Jr. and Eddie E. Scott ABSTRACT 4 Claims, 6 Drawing Figures PATENTEDSEP 51912 suzznurz FIG. I B

I N VEN TOR ROBERT B. MERIPOL AGENT OIL WELL PUMP WITH-PERMANENT CONNECTIONS AND A PLUNGER THEREFOR BACKGROUND OF THE INVENTION This invention relates to the field of pumping liquids from oil wells and more particularly to an improved sucker rod pump with a novel plunger therefor.

It has long been known that pumps are necessary for producing oil, or other liquid, from many wells. Over the years, a very large number of pumps of various for example, a stack of composite cloth and rubber rings are mounted on a plunger mandrel in such a way that an oil seal is created when the assembled plunger is telescoped within the barrel of the pump. Other prior plungers are of the metallic type wherein the oil seal is created by virtue of a close tolerance between the ground outer diameter of the plunger and the honed internal diameter of the barrel; these plungers are sometimes called unitary plungers. Still other plungers of the prior art have a plurality of relatively short tubular metallic sections (with very closely controlled dimensions on the inner, outer, and end surfaces) mounted exteriorly on a very accurately machined plunger mandrel in abutting relationship with each other and secured between a pair of shoulders on the mandrel wherein the oil seal dependent not only upon a close fit between the outer diameter of the plunger sections and the internal diameter of the barrel but also upon very the P p could be taken apart and repaired precise metal-to-metal joints between the abutting secmand. In fact, repair economy has been one of the primary criteria in the design of sucker rod pumps for many years.

l have developed a stronger pump, better able to withstand the hydrostatic and hydraulic forces to which a pump is subjected in pumping oil from a well, by replacing the multitude of threaded joints with swaged joints. At least one of the reasons for obtaining a stronger pump by using swaged joints is that the stress concentrations due to the notch effect produced by threading are eliminated. Since swaged joints are not demountable, my pump is not repairable. In other words, in designing this pump. 1 have chosen to go contrary to long established rules in this art.

The use of swaged rather than threaded joints in sucker rod pumps results in numerous improvements in such pumps. The pumps are not only stronger pumps but also are significantly less subject to fatigue failures of the various parts, particularly in the various joints. Since there is no need to provide for threads, the pump parts may be made of material which has a lower tensile strength and thinner sections than usual, thereby significantly reducing the cost of the materials making up the pumps. The elimination of the threads also materially reduces the manufacturing labor cost, since highstrength threaded joints require very close tolerance machining with consequent high labor cost. The use of lower tensile strength materials in the new pump also substantially increases its corrosion resistance, since such materials are less subject to attack by the corrosive fluids present in'many oil wells. Since swaged joints can be made much shorter than threaded joints with comparable strength, it is possible to design the new pump so that the standing and traveling valves are much closer together at the bottom of the pump stroke thereby obtaining a much higher compression ratio than was feasible with the prior art pumps. The use of materials with thinner sections significantly increases the areas of the liquid flow passages in the pump thereby reducing the forces which must be supplied to the pump to operate it. This, of course reduces the likelihood of failures in the sucker rod string due to excessive forces.

Since many prior art sucker rod well pumps have been developed, there have naturally been a great variety of plungers developed for use therein. Some of the prior plungers are of a soft-packed variety wherein,

tions and between the mandrel shoulders and the end sections. These prior sectioned plungers were a significant advance over the prior unitary plungers, since they are substantially cheaper to build and maintain the good operating characteristics. It is significantly cheaper to machine a relatively short tube to very exacting dirnensions than it is to machine a long tube to the same dimensional accuracy. To provide adequate wear capabilities of the plunger relative to the barrel, the plunger (whether sectioned or unitary) is ordinarily heat treated to harden it. The heat treating processes are, of course, much simpler for the individual short plunger sections than for the much longer unitary plunger.

I have found a new way of mounting plunger sections on a mandrel whereby it is no longer necessary to machine the plunger sections to such extreme dimensional accuracy and to match accurately the ends of each section. In my improved plunger, I provide resilient mounting means between the plunger sections and the mandrel. This resilient mounting serves two functions, namely, to permit radial movement of the sections relative to the mandrel and to provide the oil seal required between the sections and the mandrel.

SUMMARY OF THE INVENTION It is an object of this invention to provide a stronger oil well pump of the type that is operated by sucker rods extending between the pump and a pumping unit on the surface of the earth.

It is further object of this invention to provide an improved plunger for an oil well pump.

These objects and others which will be apparent to those skilled in this art are accomplished by means of an oil well pump which consists of an outer tubular barrel with a tubular plunger telescoped therein in close fitting relationship whereby an oil seal is efiected between the barrel and the plunger. The pump includes a pair of check valves one of which is attached to the barrel and the other is attached to the plunger; the attachments may be effected by swaged joints. A top connecu'on adapted for connection to the lower end of a sucker rod string is attached by means of a swaged joint to either the barrel or the plunger depending on whether a traveling barrel or traveling plunger pump is desired. A pump holddown means is attached by means of a swaged joint to either the barrel or plunger depending on the type of pump desired.

The plunger for the improved oil well pump may be of conventional construction or may be my improved plunger which includes a tubular mandrel with at least one tubular plunger section resiliently mounted on the outside of the mandrel and secured against longitudinal movement relative to the mandrel by means of retainers attached to the mandrel by means of swaged joints.

The characteristics and advantages of the invention are further referred to in connection with the accompanying drawings, which represent certain embodiments. After considering these examples, skilled persons will understand that variations may be made without departing from the principles disclosed and I contemplate the employment of any structure or arrangement that is properly within the scope of the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS DESCRIPTION OF THE PREFED EMBODIMENTS Referring now to FIGS. 1A and IE, it is seen that FIG. lA represents the upper portion and FIG. 1B the lower portion of a traveling plunger sucker rod pump 2 with a bottom holddown means 4. The pump holddown means 4 has been shown as a conventional three-cup type, but it should be understood that any of the usual forms of pump holddown means may be used, for example, any of the suitable mechanical holddown means may also be used. In the claims, the pump holddown means element is meant to include either a cup type or a mechanical type or any other suitable holddown mechanism as well as a simple tubular coupling which has a threaded connection on one end to which any conventional holddown means may be attached.

The three-cup type holddown means 4 includes a tubular mandrel 6 with an outer surface substantially as shown in FIG. EB and three elastomeric seal cups 8 separated by a pair of seal cup rings 10. The cups 8 and rings iii are held in place on mandrel 6 by means of nut 12 and lock nut 14. Lock nut 14 has internal threads on its lower end to which a tailpipe may be attached, if desired. Further description of the holddown means 4 is not considered necessary since it is conventional and forms no part of my invention.

A thin wall tubular metal pump barrel 16 is telescoped over the exterior of the upper end of holddown mandrel 6 as shown and secured thereto by means of a swaged joint 18. The swaged joint 18 is shown in H6. lB with square ends and of a relatively long length for simplicity. In practice, of course,

' swaged joint id (as well as the other swaged joints and restrictions discussed below) has rounded rather than square ends and is of a relatively short length. An 0- ring seal 2d is provided near the upper end of holddown mandrel 6 to prevent the flow of fluids between the mandrel 6 the the barrel 116.

A standing valve 2?; (usually in the form of a ball check valve) is inserted into the barrel 16 to the point that its lower end abuts against the upper end of the holddown mandrel s and is secured in this position by means of a restriction 32 swaged into the barrel 16 as shown in FIG. 1B. Hereafter, such restrictions as this are often called swaged joints. The standing valve 22 includes a ball guide 24, a valve member (ball) 26 and a valve seat 28. The ball guide 2d is of the closed type, i.e., it has a plurality of outlet passages in its upper surface whereby liquid (oil) after passing through the standing valve remains in the barrel. The pump artisan will note that, contrary to prior practice, standing valve 22 does not include a valve cage; instead in my pump, the barrel acts as the cage. An O-xing seal 36 is provided in the outer surface of the valve seat to prevent the flow of fluids between the exterior of the valve seat and the barrel 116.

An elongated, tubular plunger 34 is telescoped within barrel lo. Plunger 34 may take the form of any of the prior art plungers discussed above; however, I prefer to use my improved plunger which is shown in FIGS. Mr and i8 and described hereafter.

Plunger 34 includes an elongated, tubular, metallic mandrel 36 with a traveling valve 3% secured in one end thereof. Traveling valve 333 includes a tubular cage 48 which is secured to one end of the plunger mandrel 36 by means of swaged joint 50 and a check valve comprising a ball guide d d, a valve member (ball) 42 and a valve seat dd such as are used in conventional traveling valves. If a flow passage with a reduced flow area is acceptable in the traveling valve, the separate cage 48 may be eliminated and the valve retained in the plunger mandrel 36 similar to the way the standing valve is retained in the barrel of this pump. As shown in FIG. 18, ball guide 443, valve member 42 and valve seat 44 are inserted into cage db and secured against longitudinal movement therein by a tubular seat retainer 52 which is retained in cage as by means of a swaged joint 54. Ball guide dill is a closed type guide. O-ring seals 46 and 56 are provided to prevent the How of fluid between the cage and the valve seat 44 and the plunger mandrel 1%, respectively.

In my improved plunger, as shown in FIGS. 1A and 13, a plurality of resilient mounting means 58 are provided on plunger mandrel 36 so spaced that they support tubular plunger sections 6%!) near each end thereof when the plunger sections are telescoped over the outside of plunger mandrel 365.

Each of the resilient mounting means 58 comprises an annular depression 62 swaged into the outer surface of the plunger mandrel 36 and an O-ring 64 in the depression as shown in detail in FIG. 3. Those skilled in this art will, of course, recognize that the resilient mounting means 5% may include an O-ring groove in the outer surface of the plunger mandrel 36 or an O- ring groove in the inner surface of the plunger sections 66 rather than the preferred depression 62 (see FIG. 4). As noted above, the resilient mounting means 58 are the heat of my improved plunger. The use of the resilient mounting means permits the manufacture of a sectioned plunger at a drastically reduced cost when compared with the prior sectioned plungers, both in connection with the cost of machining the sections and the mandrel (the adjacent surfaces of the sections and the mandrel need not be machined to such close tolerance) and in the cost of assembling the complete plunger. In addition to reducing the cost of the plunger, the resilient mounting means leads to a significantly improved plunger as far as its use in a sucker rod pump is concerned.

The outer diameter of the plunger sections 60 and the inner diameter of the barrel 16 are dimensioned so that, when the complete plunger 34 is inserted into barrel 116, an oil seal is-effected by virtue of a small clearance between the outside diameter of the plunger sections 60 and the internal diameter of the pump barrel 16 at least for the portion of the barrel represented by the stroke of the plunger during operation of the pump. The resilient mounting means 58 provide the required oil seal between the plunger sections 66 and the plunger mandrel 36. The internal diameter of plunger sections 60 need not be-precisely concentric with the outside surface of the plunger mandrel 36 (as is necessary in all prior sectioned plungers), since the resilient mounting means 58 permit compensations for variations in concentricity as well as dimensions. It is readily recognized that, because of the resilient mounting means 58, each plunger section 60 may tilt with respect to'its axis while the plunger is being inserted into barrel l6 and, once in the barrel, the plunger sections 60 will align themselves in mating configuration with the barrel because of the floating nature of the resilient mounting means 58.

Plunger sections 60 are retained on mandrel 36 by means of a tubular plunger section retainer 66 which engages the upper end of the uppermost plunger section 66 and keeps the ends of adjacent plunger sections 66 in engagement with each other as well as the lower end of the lowermost plunger section 60 in engagement with the upper end of cage 48 as shown in FIGS. 1A and 1B. Longitudinal movement of the plunger section retainer 66 is prevented by means of a swaged joint 68.

Plunger sections 60 may have the cylindrical outer surfaces described and shown above or may have other suitable outer surface configurations. For example, the grooved, resilient rib structure shown in U.S. Pat. No. 3,l46,725 issued to J. W. Harris may be used.

A top connection 70 is attached to the upper end of mandrel 36 by means of a swaged joint 72 as shown in FIG. 1A. Connection 70 is adapted for connection to the lower end of a sucker rod string (not shown), for example, by means of threads 74 whereby the plunger may be reciprocated and thereby pump oil from the well. A plurality of ports 76 is provided in top connection 70 so that the oil may pass from the interior of the plunger mandrel 36 into the tubing and thence to the surface through the tubing (not shown).

It is frequently desirable to include a clutch mechanism in a sucker rod pump. Such clutch mechanisms are provided to permit the well operator to manipulate the pump to a clutching position wherein rotation of the plunger relative to the barrel is prevented so that, for example, the multitude of joints between adjacent sucker rods in the string may be tightened or retightened by applying torque at the top end of the sucker rod string which torque will be backed up by the pump. A suitable clutch mechanism for my pump is illustrated in FIG. HA and includes a pair of clutch pins 78 welded to the exterior of plunger mandrel 36 and a tubular clutch sleeve 80 secured to the top end of barrel 16 by swaged joint 82. Sleeve 80 has a pair of cutouts in the upper end which are adapted for engagement with clutch pins 78.

FIGS. 2A and 2B are representations of a traveling barrel sucker rod pump 162 with a bottom holddown means 4. Comparison of the traveling plunger pump 2 shown in FIGS. 1A and 118 with a traveling barrel pump 102 shown in FIGS. 2A and reveals revesals a further very important advantage of my improved sucker rod pump. The replacement of threaded connections with swaged connections permits one to assemble either a traveling plunger or a traveling barrel pump from exactly the same collector of parts with the single exception of the inexpensive valve seat retainer for the traveling valve. For this reason, the parts shown in FIGS. 2A and 2B have been identified with the same reference numbers as was used in connection with FIGS. 1A and 13. Some of the parts have been identified with a number plus an a to signify the part is similar in function to the corresponding part in FIGS. IA and 1B but is used in a different position or has different dimensions.

This parts interchangeability feature of my invention provides a very important economic advantage to the manufacturer of my pump, since he is not required to make and keep an inventory of parts for each type of pump. For example, for each pump size, two different barrels are required for the prior pumps-one with the threaded connections corresponding to a traveling plunger pump and another barrel with the threaded connections appropriate for a traveling barrel pump, whereas for my pump a single barrel is sufficient. Further, for my pump, the manufacturer need provided fixtures for many fewer sizers of swaged joints than he would need for a threaded joint pump. For example, for a 1% inch pump, he need provide only four different swaging dies to make all of the joints for either a traveling barrel or a traveling plunger pump whereas, using threaded joints, at least 14 different sizes of threads must be machined.

It will be recognized that the swaged joints are in different places in the two pumps and therefore have been assigned different reference numbers.

The locations of various O-ring seals are different between the two types of pumps and hence have been assigned difierent reference numerals in FIGS. 2A and 28.

Since in a traveling barrel pump the plunger is stationary while the barrel reciprocates during operation of the pump, the tubular plunger mandrel 36 of traveling barrel group 162 is telescoped within the holddown mandrel 6 and secured thereto by means of a swaged joint 1 as shown in FIG. 2B. An O-ring seal 106 is provided near the upper end of holddown mandrel 6 to prevent the flow of fluids between the holddown mandrel 6 and the plunger mandrel 36. Space for the O-ring is provided by swaging a depression in plunger mandrel as.

A standing valve 22a is attached to the other end of plunger mandrel 36. Standing valve 22a is composed of the parts used for the traveling valve 38 of the traveling plunger pump 2 shown in FIGS. 1A and 1B, namely cage 48, ball guide 40, ball 42, valve seat 44 and O-ring seal 46. Cage 48 is secured to the plunger mandrel 36 by means of swaged joint 108. An O-ring seal 110 is provided near the upper end of plunger mandrel 36 to prevent the flow of fluids between mandrel 36 and cage 48. The space for the O-ring of seal 1110 consists of a depression swaged into the mandrel 36.

it will be recogiized, of course, that plunger sections 66 are mounted on plunger mandrel 36 (as was described in connection with FIGS. 1A and 13 above) prior to installation of standing valve 22a. Plunger sections 6% are secured against longitudinal movement in the traveling plunger pump 2 shown in FIGS. 1A and 3 1B, namely, ball guide 24, ball 26, valve seat 28 and O- ring seal 30. Traveling valve 38a is secured against longitudinal motion in the barrel by means of a tubular seat retainer 52a which abuts the lower end of traveling barrel 38a and is secured to barrel 16 by means of swaged joint 116. Retainer 52a is similar to retainer 52 used with the traveling valve of the traveling plunger 2; the only significant difference is that it has a diameter appropriate to the barrel rather than to the plunger mandrel.

The pump barrel 16 after the top connection 70 and traveling valve 38a are secured thereto is telescoped over the exterior of plunger 34 and the lower end of the barrel 16 is attached to the clutch sleeve 80 by means of swaged joint 82 and to complete the assembly of the traveling barrel pump 102 as shown in FIGS. 2A and 28.

Since those skilled in the sucker rod pump art will readily understand the operation of the abovedescribed improved traveling plunger and traveling barrel pumps, I do not consider it necessary to belabor this specification with a description of the operation of these pumps.

It is to be understood that the foregoing is illustrative only and that my invention is not limited thereto, but may include various modifications and changes which may be made by those skilled in this art without departing from the scope of my invention as defined in the claims.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

H. An oil well pump of the type which is operated by sucker rods extending between a pumping unit on the surface and the pump in a well comprising:

an outer barrel in the form of an elongated tube;

a tubular plunger telescoped within said barrel and tightly fitting therein whereby an oil seal is effected between the internal diameter of said barrel and the outer diameter of said plunger, said tubular plunger comprising:

a tubular mandrel; and

at least one tubular plunger section resiliently mounted on the outside of said mandrel and secured against longitudinal movement relative to said mandrel by means of plunger section retainers attached to said mandrel;

a pair of check valves, one of which being attached to said barrel and the other being attached to said plunger, said attachments being effected by swaged joints;

a pump holddown means attached by means of a swaged joint to one end of one of said barrel and said plunger; and

a top connection adapted for connection to the lower end of a sucker rod string and being attached by means of a swaged joint to the one of said barrel and said plunger which is not attached to said pump holddown means,

2. The apparatus described in claim 1 wherein said plunger section retainers are attached to said mandrel by means of at least one swaged joint.

3. Anoil well pump of the type which is operated by sucker rods extending between a pumping unit on the surface and the pump in a well comprising:

an outer barrel in the form of an elongated tube;

a tubular plunger telescoped within said barrel and tightly fitting therein whereby an oil seal is effected between the internal diameter of said barrel and the outer diameter of said plunger, and tubular plunger comprising:

a tubular mandrel;

a plurality of tubular plunger sections telescoped on the exterior of said mandrel in abutting relationship with one another;

resilient mounting means mounted on said mandrel near each end of said plunger sections whereby fiuid is prevented from flowing between said mandrel and said plunger sections and whereby said plunger sections are mounted on said mandrel and may move slightly in the radial direction relative to said mandrel when said plunger is inserted into said barrel to form the oil well pump; and

plunger section retainer means attached to said mandrel whereby said plurality of plunger sections are prevented from longitudinal motion relative to said mandrel;

a pair of check valves, one of which being attached to said barrel and the other being attached to said plunger, said attachments being effected by swaged joints; pump holddown means attached by means of a swaged joint to one end of one of said barrel and said plunger; and a top connection adapted for connection to the lower end of a sucker rod string and being attached by means of a swaged joint to the one of said barrel and said plunger which is not attached to said pump holddown means.

4. The apparatus described in claim 3 wherein said plunger section retainer means is attached to said mandrel by means of at least one swaged joint. 

1. An oil well pump of the type which is operated by sucker rods extending between a pumping unit on the surface and the pump in a well comprising: an outer barrel in the form of an elongated tube; a tubular plunger telescoped within said barrel and tightly fitting therein whereby an oil seal is effected between the internal diameter of said barrel and the outer diameter of said plunger, said tubular plunger comprising: a tubular mandrel; and at least one tubular plunger section resiliently mounted on the outside of said mandrel and secured against longitudinal movement relative to said mandrel by means of plunger section retainers attached to said mandrel; a pair of check valves, one of which being attached to said barrel and the other being attached to said plunger, said attachments being effected by swaged joints; a pump holddown means attached by means of a swaged joint to one end of one of said barrel and said plunger; and a top connection adapted for connection to the lower end of a sucker rod string and being attached by means of a swaged joint to the one of said barrel and said plunger which is not attached to said pump holddown means.
 2. The apparatus described in claim 1 wherein said plunger section retainers are attached to said mandrel by means of at least one swaged joint.
 3. An oil well pump of the type which is operated by sucker rods extending between a pumping unit on the surface and the pump in a well comprising: an outer barrel in the form of an elongated tube; a tubular plunger telescoped within said barrel and tightly fitting therein whereby an oil seal is effected between the internal diameter of said barrel and the outer diameter of said plunger, and tubular plunger comprising: a tubular mandrel; a plurality of tubular plunger sections telescoped on the exterior of said mandrel in abutting relationship with one another; resilient mounting means mounted on said mandrel near each end of said plunger sections whereby fluid is prevented from flowing between said mandrel and said plunger sections and whereby said plunger sections are mounted on said mandrel and may move slightly in the radial direction relative to said mandrel when said plunger is inserted into said barrel to form the oil well pump; and plunger section retainer means attached to said mandrel whereby said plurality of plunger sections are prevented from longitudinal motion relative to said mandrel; a pair of check valves, one of which being attached to said barrel and the other being attached to said plunger, said attachments being effected by swaged joints; a pump holddown means attached by means of a swaged joint to one end of one of said barrel and said plunger; and a top connection adapted for connection to the lower end of a sucker rod string and being attached by means of a swaged joint to the one of said barrel and said plunger which is not attached to said pump holddown means.
 4. The apparatus described in claim 3 wherein said plunger section retainer means is attached to said mandrel by means of at least one swaged joint. 